Membrane voltage becomes less negative, moving closer to the threshold potential, making it EASIER to initiate an action potential.

膜电压具有较小负值，接近阈值电位，这样，更容易启动动作电位。

But eventually, the resting membrane potential gets so high that it's above the threshold potential, meaning that once the muscle depolarizes and contracts, it can't repolarize to allow another contraction.

但最终，静息电位变得太高，以至于超过阈值点位，这意味着一旦肌肉去极化收缩，就不能复极化以进行下一次收缩了。

Excitatory neurotransmitters depolarize the postsynaptic neuron by making the inside of it more positive and bringing it closer to its action potential threshold, making it more likely to fire that message on to the next neuron.

兴奋性神经递质通过使突触后神经元内部更加积极并使其更接近其动作电位阈值来去极化突触后神经元，使其更有可能将该信息发送到下一个神经元。